Heavy fighting has continued in the centre of Misrata as rebels fight off a continued onslaught by government forces on the besieged city. Nato said it had destroyed 12 of the Gaddafi regime's tanks there.

"Today seems good, the rebels are making progress in the clashes and we can see plumes of smoke rising from several [government] forces' positions," a rebel spokesman, who identified himself as Gemal Salem, told Reuters.

Nato, which has been urged by Britain and France to intensify its efforts around Misrata and Ajdabiya, said a total of 16 government tanks had been hit by air strikes.

British defence officials said RAF Typhoons had fired weapons for the first time, attacking two Libyan tanks with 1,000lb bombs.

The long-delayed Typhoon, conceived in the 1980s to engage in dogfights with Soviet aircraft over northern Europe, has been adapted as part of a £37bn project to take on a ground attack role.

Six Typhoons – four assigned to Nato – are stationed at Gioia del Colle, an airbase in southern Italy, along with 12 Tornados. The aircrafts' first bombing mission hit tanks near Misrata on Tuesday evening.

In addition to the 12 tanks in Misrata, four tanks, a pickup truck and an anti-aircraft gun were destroyed near Sirte, Muammar Gaddafi's home town, Nato said. Its aircraft have flown 159 sorties, including 60 strike missions, over Libya.

The first TV footage shot in Misrata, broadcast by ITN on Tuesday, showed deserted streets and buildings scarred by shells and gunfire. A reporter, John Irvine, said rebels appeared to be holding out against the onslaught, although civilian casualties were high.

Both rebels and government forces have used snipers over the past month, and many of the injured brought to the city's struggling hospitals have gunshot wounds. Unicef has warned that thousands of children are at risk in the city, and that conditions for residents under siege are desperate.

The Libyan government, which has refused to allow journalists based in Tripoli to enter the city, said it was "doing its best to help the people of Misrata trapped by terrorists and armed gangs".

A government spokesman, Moussa Ibrahim, said: "We insist we are doing everything we can." However, he added, the government was hampered by "unnecessary, illegal and immoral" Nato air strikes and gangs "terrorising the streets of Misrata".

Libyan state TV said Nato military planes had struck targets in Al-Aziziya and Sirte. Several explosions had been heard over Tripoli.

Sign up for the Guardian Today

Our editors' picks for the day's top news and commentary delivered to your inbox each morning.